Some semiconductor materials such as silicon carbide (SiC) show significantly higher dielectric breakdown field strength than silicon such that the extension of a drift zone along the on-state current direction can be made smaller than for comparative silicon devices. For example, vertical power semiconductor devices with a load current flow between a first surface at the front side and an opposite second surface of a semiconductor body from semiconductor materials with high dielectric breakdown field strength can be made to have a significantly thinner drift zone and/or a higher doping concentration in the drift zone such that they can combine very high breakdown voltages of more than 600 V with lower on-state resistance than comparative devices based on silicon. The high breakdown voltage also results in that a stress the gate dielectric in a SiC-MOSFET (silicon carbide metal oxide semiconductor field effect transistor) is exposed to differs from the stress in the gate dielectric of comparative silicon devices.
It is desirable to improve power semiconductor devices from semiconductor materials with high dielectric breakdown field strength in view of gate dielectric reliability and on-state resistance.